It is well known in the art of torque converters for a torque converter to have a housing that comprises a cover and an impeller shell. It is also known in the art of torque converter clutch design to have an internal component fixedly attached to the housing in order to transmit torque from the housing to mating components, such as, clutch plates. In one particular design, the internal component is an annular plate, orthogonal with respect to the torque converter's axis of rotation, attached to the housing via mechanical fasteners, such as, splined engagements, or via metal inert gas (MIG) welding, tungsten inert gas (TIG) welding, or laser welding, or some combination thereof. When the housing rotates, it transmits torque to the plate. The plate, in turn, transmits the torque to mating components, which are generally a stack of annular clutch plates, through one or more frictional engagements therebetween. Unfortunately, prior torque converter clutch designs of this type suffer from a number of drawbacks.
For example, U.S. Pat. No. 6,688,441 (Arhab) discloses a torque converter with an annular plate fixedly attached to the housing of the torque converter for transmitting torque to mating components. Arhab discloses a number of embodiments, each of which suffers from one or more drawbacks. FIG. 1 of the Arhab patent shows a torque converter housing wherein an annular front axial skirt of the front shell (cover) extends past an annular torque-transmitting plate component, to which it is attached via a weld seam. It overlaps the annular rear axial skirt of the rear (impeller) shell, to which it also attached via a weld. One drawback of this embodiment is that the front shell (cover) is costly to manufacture, especially if it is stamped piece. A cover with an axial skirt long enough to overlap both the plate and the impeller shell uses an excessive amount of raw material, which is costly and renders the overall torque converter excessively heavy. Further, if the cover is a stamped piece, which it generally is, a long axial skirt is often unintentionally deformed during manufacture due to the resistance of the cover material to the stamping process, colloquially known in the art as “potato chipping”. Further, the various types of welding used to attach the housing to the torque-transmitting plate component often leads to the deformation of the plate component. Additionally, in designs wherein the cover overlaps the impeller shell, or vice versa, the overall radial package of the torque converter is excessive.
FIGS. 5, 7, and 9 of the Arhab patent show embodiments wherein the housing is attached to the torque-transmitting plate mechanically, for example, via splined engagements or retaining rings. Mechanical fasteners are inherently prone to rattling during operation because the components, while well-machined, are not fixedly attached to each other and vibrate and/or hit against each other during operation.
FIGS. 11 and 16 of the Arhab patent show embodiments wherein the cover is welded to the torque-transmitting plate on the interior of the torque converter. Welding in the interior of a torque converter leads to undesirable contamination within the torque converter which adversely affects its operation.
Thus, there is a long-felt need for a torque converter, wherein its housing is fixedly attached to an internal torque-transmitting plate, and does not suffer from the drawbacks described above. In particular, there is a long-felt need for a torque converter of this type that is less costly to manufacture, creates a more stable torque-transmitting plate component that deforms less from welding, is lighter, has a reduced overall radial package, does not rattle, and reduces the risk of internal contamination via welding its components primarily on its exterior.